The present invention generally relates to an electronic component such as a variable resistor or a variable capacitor, which includes a rotor, a stator and a casing.
There has been conventionally known such a variable resistor of the type referred to above which includes a rotor, a stator and a casing, as shown in FIGS. 4 and 5. In this variable resistor an insulative stator 1 has a resistive member 1a and a collector electrode 1b formed on the surface thereof. A first lead terminal 2 is electrically connected to an end of the resistive member 1a, a second lead terminal 3 to the other end of the resistive member 1a, and a third lead terminal 4 to the collector electrode 1b, respectively.
A slider 5 is arranged to slide on the resistive member 1a and the collector electrode 1b, which slider 5 is secured to a recessed portion formed in the bottom face of a rotor 6. The rotor 6 has a projected portion 6a formed in the upper part thereof to provide a driver groove 6b.
A casing 7 is designed to support the slider 5 secured to the rotor 6, through an O-ring 8, on the stator 1. The projected portion 6a of the rotor 6 is exposed outside of the casing 7 through an opening formed on the upper surface of the casing 7. The rotor 6 is rotatably retained within the casing 7, and, at the same time, the stator 1 is secured to the casing 7 by the employment of resin 9 which is obtained through potting and hardening of such resin as heat-hardening type epoxy resin or the like. Also, the resin 9 serves to increase, the air-tightness of the casing 7.
In the variable resistor having the above-described construction, the rotor 6 is rotated with respect to the stator 1 and the casing 7 by the guidance of the driver groove 6b, with the slider 5 sliding on the resistive member 1a and the collector electrode 1b.
However, the electronic component of the type represented by the above-mentioned variable resistor which has a rotor, a stator and a casing has the following disadvantages. That is, according to the prior art electronic component as described above, it is necessary for the resin 9 to be subjected to potting, which subsequently makes it necessary to permit the resin to harden for some period of time. Moreover, when the electronic component is of a sealed structure, the atmospheric pressure inside the component inevitably rises due to the heating of the resin for hardening, thereby sometimes creating holes in the potted resin 9. Furthermore, when the electronic component is small in size, it is difficult to adjust or control the amount of the resin 9 to be subjected to potting.